... hoursHailstone resistanceDia=25mmGuarantyWater tank for 5 years, tube and frame for 15 years1,vacuum tube length:47/1500mm,58/1800.2,vacuum tubes:15pcs,18pcs,20pcs ... open its valve,the tap water flow in the tank ,if the water is full,it will close the valve automatically solar collector tube for solar water heater